It is known that a bottle has a body having a substantially tetragonal cross section chamfered along corners thereof, and that the corner walls acts or operates as pillars. It has been required recently to decrease an amount of raw material resin from the view of conserving natural resources and protecting the environment. As a result, bottles of the type under consideration are required to have a reduced wall thickness.
However, if the wall thickness is reduced, conventional bottles of the type under consideration come to be short of rigidity, because they have flat and substantially vertical corner walls. Unless the corner walls are reinforced, the bottle body would happen to be crushed particularly when an internal pressure of the bottle changes and/or the bottle is subjected to an impact.
In view of the above identified problem, it is therefore the object of the present invention to provide a bottle having reinforced corner walls at the body thereof.